Short Summary

On June 23, 1961, at the Air Force Systems Command's Arnold Engineering Development Centre, Arnold Air Force Station, Tennessee, giant equipment began the task of removing tons of dirt and rock -- clearing the way for the recent newest and largest high altitude rocket test cell, that would take shape here over the next three years.

Description

On June 23, 1961, at the Air Force Systems Command's Arnold Engineering Development Centre, Arnold Air Force Station, Tennessee, giant equipment began the task of removing tons of dirt and rock -- clearing the way for the recent newest and largest high altitude rocket test cell, that would take shape here over the next three years.

Within a week of the third anniversary of the ground breaking, other ceremonies will mark the final competition of Propulsion Engine Test Cell J-4, tenth high altitude simulation unit at the Centre's Rocket Rest Facility. The unit will initially be used to test liquid-propellant upper stage rocket engines having up to half-a-million pounds of thrust.

Its underground exhaust chamber is 250 feet deep, and 100 feet in diameter.

More than 55 tons of dynamite were required to complete the excavation...to carve this gaping cavity large enough to bury a 25-story building in the face of Tennessee's Cumberland mountain plantation.

J-4 was designed by Sverdrup and Parcel of St. Louis, parent company of the Centre's operating contractor's, ARO Incorporated..on the basis of conceptual Layouts developed jointly by ARO and the Air Force. Total investment in J-4 is approximately fourteen and one-half million dollars. Construction was under the supervision of the Tullaboma Area Engineer, U.S. Army Corps of Engineers, Mobile District.

A sister unit...Propulsion Engine Test Cell J-5...a horizontal above-ground cell for testing solid-propellant rocket motors...was constructed in the last year of the same period. In effect, it is a one-million-dollar attachment that greatly expands testing capabilities of the facility.

Test in both units will be directed from this central room. Other elements such as ducting, compressors, exhaust systems and data gathering equipment...designed originally for J-4....will be used to support tests in both new cells.

Major support systems, for the most part, already had undergone operational check-out by the time J-4's ground level test engine capsule was being put into place.

The 48-foot-diameter capsule stands almost fifty feet high. Spool-like sections may ??? other permanent portions of the unit ???.

A full-scale upper state TITAN II engine is being readied for shakedown tests of the cell and support systems.

From its natural upright position in the capsule, the engine fires downward. Its exhaust -- greatly expanded due to the simulated high altitude condition...is channelled into a diffuser in the centre of the spray chamber.

Below the diffuser, the broad-brimmed cone deflects the exhaust products back upward along the chamber's outer walls; thence they are cooled by water spray, collected and pumped out near the top.

During the shakedown tests thus far, overall design specifications for the new unit have proved satisfactory.